1. Field of the Invention
The present invention relates to an apparatus and method for identifying devices acting as servers on a network. The present invention is particularly suitable for use in the management of a network, although other uses are contemplated.
2. Description of the Related Art
Data communications networks are becoming increasingly common in many technological fields. The following description is concerned with computer networks such as local area networks (LANs) and wide area network (WANs) comprising a plurality of network devices connected together by media links. It will be appreciated that the present invention may be useful in relation to other types of networks such as telecommunications networks, including wireless networks.
Computer networks typically comprise a plurality of computers, peripherals and other electronic devices capable of communicating with each other by sending and receiving data packets in accordance with predefined network protocols. Each computer or other device on a network is connected to the network media, which in the case of a LAN network may be coaxial cable, twisted pair cable or fibre optic cable. Data is communicated across the media between devices on the network by sending and receiving data packets (also known as frames) in accordance with one or more predefined protocols.
As is known in the art, data may be communicated using protocols at several different layers, which may fall broadly into the seven layers represented in the Open Systems Interconnection (OSI) model.
For example computer networks typically employ the TCP/IP group of protocols. In the TCP/IP protocols, at the bottom layers, called the Physical/Data Link layers, a LAN typically employs the CSMA/CD protocol as defined by the standard IEEE 802.2, commonly known as Ethernet. Each device on the LAN has hardware with an associated MAC or physical address. Data packets are sent and received in accordance with the CSMA/CD or MAC protocol, and such data packets identify the MAC addresses of the source and destination devices of the data packet in the header of the data packet.
To enable data, such as email messages and web pages, to be communicated over the Internet, higher layer protocols such as IP, TCP, FTP, SMTP, are employed. For this purpose, every computer is assigned an IP address, for sending and receiving communications using the higher layer standard TCP/IP protocols. An IP address is a unique, 4 byte number, assigned to a network device for the purpose of communication using the TCP/IP protocols, and the source and destination IP addresses are included in the data packet communications using higher level protocols, such as the IP protocol at the “network layer” in the OSI model. Thus, in a network connected to the Internet, each end-station or personal computer (PC) having Internet access can be identified by identifiers including a MAC address and an IP address. In addition to computers, other network devices such as those involved in network management communicate using TCP/IP protocols such as the Simple Network Management Protocol (SNMP) and also have an IP address. Thus an IP address is a convenient identifier of a physical network device involved in communications on a network.
Some network devices act as “servers”. A server is simply a device that provides a particular application service to a number of other devices called “clients”. For example, a “WEB server” (or HTTP server) is a device on a network that can provide HTML (web) pages to HTTP clients. There are a large number of application services that rely on the concept of a small number of server devices providing a service to a number of client devices. Moreover, a single device may be a server for many different applications, and a device that is a server for one application may be a client for another application.
For a particular network or group of networks, an individual is often appointed to perform network management duties. The appointed network manager, often called the “network administrator” utilises a network management station which includes network management hardware and software. In particular, the network management software application is able to access management data from managed network devices and monitors on the network using an appropriate management protocol (e.g. the SNMP protocol). The data can then be collated and displayed in selected forms, or used to generate reports etc, for use by the network administrator.
It is desirable for a network management software application to be able to automatically identify servers on a network for many purposes. For example, when displaying a list of devices or a map of devices on the managed network, it might be useful to display servers differently from clients, to enable easy identification of the servers, since servers are often more important to the network administrator. Another reason to identify servers might be so that automatic reports could be generated on the status of the servers.
In addition to the desirability to identify servers in the management of a network, the identification of servers may be useful in other contexts. For example, other types of software application may use the identification of servers to automatically perform certain tasks on the network.
For instance, an automated program running on a computer on the network may “prioritise” network traffic going to and from server devices. For example, a network switch/router may prioritise all traffic to and from a SAP server in order to ensure that SAP runs as efficiently as possible. In another example, a network switch/router may prioritise all traffic to and from an H323 server, since H323 is a protocol used for transmitting voice across a network. By prioritising traffic to and from H323 servers, all telephone conversations running across the network would be clear and not affected by delays or interruptions caused by other network traffic.
In another instance, a software application running on the network may employ different security measures for servers. For example, a firewall may prevent any user from outside the network from accessing any SAP server. The automatic identification of SAP servers is therefore desirable, as opposed to conventional manual identification.
In another example, a firewall/switch/router may record the IP address of every device which accesses an Oracle database server, in order to identify such activity. The automatic identification of Oracle database servers using the present invention thus enable the provision of an automatic security log of all activity which could later be viewed by the network administrator.
Some other uses of the present invention include the identification of the address of an SMTP server for the purpose of a device on the network sending an e-mail. In addition, in some network management applications, the user may be required to enter the address of a certain type of server. A default value may be provided, in accordance with the present invention, which the administrator can then override, if appropriate.
The skilled person will appreciate that the present invention may be used in contexts other than the examples described above.
There may be many ways to identify servers for a particular application. For example, for a particular application, the application protocol itself may include some way to discover the server for the application. However, identifying servers in this way requires specific knowledge of the application and may not be possible in many circumstances.